Method of making filter members



Feb. 19, 1946. E. c. SLOAN METHOD OF MAKING FILTER MEMBERS Filed Aug. 3, 1940 2 Sheets-Sheet 1 Feb. 19, 1946. E, c, SLOAN L 2,395,301

METHOD OF MAKING FILTER MEMBERS Filed Aug. 5, 1940 2 Sheets-Sheet 2 I I 'n: I

I WW ill R BY odwwid voz m Patented Feb. 19, 1946 UNITED STATES PA ENT OFFICE 2.395.301- mrrnon or MAKING m'rnn mnmens Edward O. Sloan. Geneva, Ill, assignor to Jesse B. Hawley, Geneva,

Application August a, 1940,- Serial No. 350,491

. 3 Claims.

This invention relates to a filter and to the method of producing the same. Among the obiects oi the present invention is the production of a novel filter of fibrous material in which the degree of porosity is efiectively controlled.

A further object is to accrete one at a time (into porous formers in a fibrous pulp bath a plurality of shell carcasses and so treating the fibers that the treating material will be uniformly distributed on the fibers throughout the carcass. These shell carcasses may be made separately and subsequently fastened at their edges as in Figs. 4 and 5,. or laminated as in Fig. 7, as desired.

A still further object is to dissolve a resin in the bath of fibers and water, and secrete a shell carcass onto a former oi the desired form, so that when the water is evaporated by drying, the resin will be uniformly distributed on the fibers throughout the carcass.

Another object is to add in suitable amount in. the bath of fibers and water, diatomaceous earth thoroughly mixed in the bath, so that the diatomaceous earth will control the degree of porosity or a carcass accreted onto a former immersed in the bath.

Still another object is to mix in a fibrous pulp bath diatomaceous earth, and resin in solution, to cause the diatomaceous earth to remain uniiormly distributed throughout the fibrous struc.

ture of a carcass accreted onto a former oi the desired shape in the bath.

An additional object is to add, in the desired manner resin of the desired kind, to a fibrous pulp bath, so that in a carcass accreted onto a porous former in said bath, and when dried, the resin will stabilize the fibers and the structure and keep the fibers from softening or swelling in the presence of water, thus waterproofing the fibers.

Such softening or swelling would be undesirable because it would decrease the porosity of the structure. By the present invention the resin Will add to the rigidity of the fiber structure, thus further waterproofing the fibers and causing the corrugations or other roughened surfaces to remain stiff and eflective in the presence of water, and further will keep the structure from rupturing under pressure.

A further object is to so treat the fibers as such in the bath and thus aflord the opportunity to stiffen the fibers by the use of the proper and desirable resins so that the accreted dried structure will have a decidedly indefinite, irregular, indeterminate, rough and shaggy surface to lessen the possibility of a coating or film being formed to close oi! the porosity.

iii

A still further object is to provide a multiple stage filter in which the-various stages each comprise a pair of fibrous shells for eflecting a certain selected stage of filtering.

A' further object is to provide a filter in which a large mass of fibers is accreted in a bath, either with or without resin, onto a perforated core, spool or the like to enable such filter to be easily inserted within a filter casing and readily removed therefrom for renewal when desired and, if desired, such filter may have a plurality of layers of different porosity.

Another object is to first accrete onto a porous former a fibrous article in a hath not containing resin, and then remove the article thus accreted to a second bath containing resin, and by suction or pressure cause some at the liquid in the resin bath to pass through the interstices of the fibrous article to supplant the water among the fibers of said article.

Other objects, advantages and capabilities will later more fully appear.

I have shown therein preferred embodiments, I

I wish it understood that the same are susceptible of modification and change without departing from the spirit of my invention.

In the drawings:

Figure 1 is a fragmentary longitudinal section of a portion of a filter member embodying my invention.

Fig. 2 is a similar view of another form of my invention.

Fig. 3 is a similar View of still another form of my invention.

Fig. 4 is a vertical longitudinal section showing a single stage filter member with parts broken away for convenience.

Fig. 5 is a view similar to'Fig. d, but showing a multiple stage filter member embodying my invention. I

Fig. 6 is a vertical longitudinal section through a filter casing and filter member therein, the filter member being of the mass type instead of the shell type shown in the preceding views.

Fig. 7 'is a perspective view of the filter member of the type shown in Fig. 6.

Fig. 8 is a transverse, vertical section through a tank containing a felting bath and a porous felting former, and a transferrer thereabove for car- -rying an accreted carcass from the first bath to a second bath for further treatment.

Fig. 9'i a view similar to Fig. 8 but showing a of an oven or the like for drying the wet carcasses.

, do not wish the invention to be unnecessarily limited thereto.

Referring more in detail to the drawings, Fig. 1

showsinsection a fragment of a wall of a ,filter member embodying one form of my invention. In this form the filter member is preferably formed by accreting it in a fibrous pulp bath onto a porous former of the desired shape by a differential of pressure which may be applied as a partial suction or otherwise as desired. In Fig. 1 the first layer of the filter member may b a screen I of metallic or textile material as desired placed against the porous outer surface of the former in the pulp bath; or this inner screen'may be omitted if desired. As any shape or type of porous former desired may be used, and as the suction of fibers onto a porous former in a pulp bath is well known, I have shown in Fig. 8 a simple form of apparatus for the general operation of felting or accreting a fibrous pulp carcass or shell in a bath, but without limiting the present invention to the particular shapes shown.

In producing the filter wall hown in Fig. 1 inert material such as diatomaceous earth is mixed into the fibrous pulp bath, without the addition into the bath of any resin. As the fibers and diatomaceous earth are sucked or otherwise forced against the surface of the porous former the earth particles 2 will pass through the interstice of the deposited fibers and become more or less concentrated near the inside surface of the filter carcass being formed, leaving the fibers 3 of the outside portion of the carcass more porous, and those on and near the inside surface leSs porous. In a filter of this type the outer, more porous portion of the filter wall will filter out the larger suspended matter in the fluid being filtered, while the less atomaceous earth, vermiculite, kieselguhr, fullers earth, and the like. Also it is to be understood that while my invention preferably contemplates the use of my novel filter members in filtering oil and the like, it is not to be limited thereto, but may be used for filtering any fluids to which my filter members may be adapted.

Another form of my invention is shownin Fig. 2 in which a suitable resin is added to the fibrous pulp bath. as a result of which I have discovered that the inert material is given uniform dispersion and distribution throughout the interstices of the fibers, instead of concentrating on the inner layer as in Fig. 1. In Fig. 2 the inner screen member I may be used or omitted as desired. and as shown in this view of the drawings the particles of inert material 2' are distributed uniformly throughout the fibrous wall. This phenomenon of the uniform distribution of the particles of inert material when resin is used in the bath is of great importance in that it enables close control of the porosity by controlling the kind and amount of inert material used. A water soluble resin is preferable but I Some of the resins that are suitable-in carrying out my invention include phenol formaldehyde. cresylic acid formaldehyde, meta-para cresol, urea formaldehyde, thio urea formaldehyde, and the like, or the foregoing with furfural replacing the formaldehyde; these resins being in the A" stage in which the condensation has been arrested before the resin has become hydrophobic. These resins may be dissolved in water so that the percentage of solids is from 3% to 7% by weight ,which amount of solids will be sufilcient for the stiffening, water-proofing and giving of wet strength to the fibers of the filter members as more fully described later herein.

In Fig. 3 is shown a fragment of a portion of the fibrous filter member wall in which the surface first meeting the oil or other fluid being filtered is extremely rough, shaggy, indefinite, indeterminate or irregular as indicated at 4 so as to lessen the possibility of a coating or film being formed to close off the porosity, as a film forming substance would have the tendency to attach itself to the-first part of the surface with which it comes in contact. The porosit away from the surface of the filter may be great or less as desired. A given amount of film forming material will have less tendency to form a continuous film-and thus close of! or stop the effectiveness of the filtering area-where the indefinite or shaggy surface is present as in Fig. 3 to filter out the film forming material. This tendency to prevent the formation of a film on the filter surface may be better understood by likening it to the uneven, shaggy appearance of a lawn of more or less high grass in the spring when a light fall of snow falls on the same.

In Fig. 3 as in Fig. 2, resin is added to the pulp bath from which the filter member is accreted. As stated water-soluble resin is preferred. This resin is dissolved in the bath in desirable proportion. A suitable proportion is to dissolve 5% by weight of solid resins in the bath water in which the fibers to be accreted on the former are suspended. When accreted or felted and prior to drying a 30 gram filter carcass will have approximately grams of water containing 5% solid resin. When the carcass is dried the 5% or 4 grams of resin remains in the carcass or filter shell, distributed uniformly throughout the fibers. The resin has also to a certain extent entered the fibers themselves as well as coating and joining the fibers. This method of treating the fibers as such in the bath Waterproofs the fibers byusing the proper resins and stifiens the fibers.

A further advantage in treating the fibers of the'filter unit with resin is that the resin stabilizes the fibers and the structure, and prevents the fibers from softening or swelling in the presence of water, should some water pass through the interstices of the filter when filtering oil or other fiuids. Should the fibers become soft or swell (as they will not do with the present invention) this would decrease the porosity of the structure which is undesirable, and might even lead to the rupture of the filter unit.

Referring back to Fig. 2, the incorporation of resin in the filter unit as described, will not only keep the inert material uniformly dispersed and distributed with relation to the fibers, but it will also allow a greater thickness of accretion with a given uniformity of porosity. The resin in the bath prevents the inert material from gathering in clusters or layers in the fibers and insures perscribed above will also render them -e,ses,soi

words, it

' l and 8 respectively are formed with registering central openings around the edges 01' the material of which are secured the strengthening and supporting collars l0 and H. These are secured together by a sleeve i2 formed with apertures 13 to permit the outflow of the filtered oil, As will be understood the accreted fibrous shells 5 and 8 may be of any of the various constructions described earlier herein, and of any desired shape. The filter unit of Fig. 4 will preferably be inserted in a filter casing ll such as shown in Fig. 6, or of any other suitable shape and construcv iden desired. In operation the oil or other fiuid to be filtered will enter the filter casing I I at i5, then pass through the shells 5 and 8 to the space it therebetween, then through the a ertures I 3 of sleeve i2 and out through any suitable outlet opening provided in the base of the filter and associated parts.

m Fig. 5 is shown a multiple stage filter unit comprising four s ells I I. l8, l9 and arran ed in two pairs of which shells l1 and I8 form one pair having a reinforcing collar 2| in the openings of the base port ons, and shells l9 and 20 form another pair having a reinforcing collar stage filter unit of Fig. 5 will be inserted in filter casing id or other suitable casing in the manner su gested above in connection with Fig. 4. In the filter unit oi! Fi 5 much greater efficiency in filtering may be achieved however because the outer and inner shells l1 and 20 may be of different construction from the intermediate shells l8 and it to give added filtering possibilities. For example, the outer and inner shells l1 and 20 may be of medium coarseness to filter out the sludge or heavier parts of the dirt in the oilpr the like, and the two intermediate shells Ill and is may be of much finer porosity so as to filter out particles which color the oil black or gray. by having a combination of fibers and inert material, or fibers, resin and inert material in their composition as desired. The oil or other fluid being filtered would first fiow inwardly through the shells ill and 20 into spaces 23 and 24 to eflect the first stage of filtering, and thence through shells i8 and i9 into space 25 and then through the outlet perforated spacer 2IA to any desired receiving means to effect the final filtering and, if desired, a brightening of the oil. Also if desired, the first stage might be composed of coarse water-absorbing fibers to absorb water that may be entrained the oil, so that water as such will not impair the emciency oi the later stage or stages. 1

My invention'further contemplates the production of filters for oil and other fluids in which the filter unit is accreted onto a perforated hollow core or spool, the accreted filter portion having considerablev mass .and thickness.

Such a filter is shown in Fig. 6 in vertical cross section.

The fibers used in accreting this type of filter are preferably rock wool, but other kinds of fibers shown the core 29 is perforated to permit the oil or other fiuid to pass therethrough (after passing through the rock wool fibers) and thence out through the outlet 26, there being provided in the walls of the hollow stud 3i openings 32 to permit the passage of the filtrate. The hollow stud 3| is threaded into the base-21 at 33 to permit tightening and removal of the parts, and above the upper cover or hub cap 34 of the spool is a coil spring 35 to force the filter unit downwardly. The spring 35 is held under compression between the cap 34 and the shoulder 36 of the head 31, there being interposed a gasket 38 between the head 31 and the filter casing cover 28 to prevent leakage. A cloth covering is preferably applied over the outside of the core 29, to prevent the fibers from passing through holes 72. in th core.

Fig. 7 shows how the accreted fibers 30 together with the core 29 may be made separate and installed in the spool when fresh and removed therefrom as a filter unit after use. Also the core 29 may have the rock wool fibers accreted thereon to any desired thickness by providing removable ends 39,40 to the core 29 while in the accreting bath to define the shape of the ends of theaccreted fibers, or other removable blank ends of the desired width may be applied to the core during accreting as desired to define the ends of the filter unit. The accreted fibers of the form of filter shown in Figs. 6 and 7 may have resin, or inert material or both in desired proportions incorporated therein during accretion, as set forth earlier herein in connection with the description of Figs. 1 to 3 inclusive, and for a sim ilar purpose. A gasket ,is provided between the outer edge of the casing cover 28 and the upper edge of the filter casing to prevent leakage. I may also provide three layers a, b and c.(see Fig. '7) of different porosity, for example, these different layers may be of diflerent fineness of fibers, and may have diatomaceous earth or the like in one or more but with resin in all of the layers. In other words, the layers will be so constructed in one or the other of the different ways heretofore described so as to have different porosity-in the difierent layers as desired, with the coarser porosity in the outer layer, a finer porosity in the next layer and a still finer porosity in the inner layer so as to give different degrees of filtering in the diil'erent layers. Any greater or less number of layers may be used as desired. My invention also contemplates the accreting of an article of fiber sheet or contoured form, in a fibrous pulp bath without resin, and then removing the article thus accreted from the first bath and immersing it into a second bath containing resin in solution in water and pulling or forcing by suction or pressure the resin solution through the said accreted article and supplanting the original water remaining in the interstices in the article, with the resin solution, and drying the article by removing the water and leaving the resin impregnation in and on the fibers.

In Fig. 8, I have shown a tank 50 containing a fiber-wate bath 5|, a porous felting former 52 being insertable into.and removable from this batli. This felting former is hollow and has mounted in its base a hose, pipe or the like 53 communicating with the interior of the porous former so as to create a suction on the interior thereof for sucking'the water through the openings in the former and depositing the fibers thereon to form a carcass or shell designated generally in Fig. 8 at IS.

The hose 53 is formed with a coil 54 in order to permit the former 52 to be moved upwardly out of the bath, or downwardly thereinto as desired. Coil 54 passes through the wall of tank 50 and connects with the manifold 55, into which extend the air pressure pipe 56 and the suction pipe 51, which latter two pipes will be connected with any suitable means of air pressure and suction. Pipes 56 and 51 are controlled by valve 58 which may be operated to connect either the air pressure line or the suction line as desired to the hose 53 so as to create either a suction on the interior of the porous former or introduce air pressure thereinto selectively. The former and wet carcass are shown in dotted lines just above the tank 50.

Above the tank 50 is a transformer 59 for receiving and transferring the wet carcass to the second tank 60 containing a fiber-water bath 6| having resin included therein. Transferrer 59 is formed on its interior with the porous shell 62 of substantially the same internal size as the exterior of the wet carcass l6, and into which hollow interior the wet carcass is introduced by moving the former 52 upwardly thereinto, after which the valve 53 will be operated to introduce from a suitable source of supply a suction in the space 64 so as to cause the wet carcass to adhere to the interior of the transferrer. If desired, this can be further facilitated by introducing air under pressure into the interior of the former to tend to force the wet carcass away from the exterior of the former 52, after which the former will be lowered again into bath 5|, the air pressure cut off and suction introduced into the former to accrete another carcass thereon.

As soon as the former 52 has deposited its wet carcass on the interior of the transferrer and the former lowered away from the transferrer, the latter will be moved by any suitable means into the position shown in Fig. 9, after which the former 65 is introduced thereinto and suction created in the former 65 to suck the wet carcass thereagainst. At the same time, the suction in the space 64 of the transferrer will be cut oil? and any desired amount of air pressure introduced through pipe 56 into space 64 to further cause the wet carcass to grip the exterior of the upstanding porous portion of former 65, thus causing the carcass to adhere to the former. The former 65 with the wet carcass thereon is shown in Fig. 9 midway between the transferrer and tank 60. The former 65 together with the wet carcass I5 thereon will then be lowered into tank 6|! into the position shown in Fig. 9, and the suction on the interior of former 65 continued so as to suck water from bath 6| through the pores of the former and through hose 54', manifold 55' and suction pipe 51' to pass liquid from bath 5| through carcass l6. Included in bath BI is resin similar to that previously described in connection with Fi s. 1 to '1.

when the carcasses are formed solely in a single bath such as shown in Fig. 8, and the bath shown in Fig. 9 not used, the resin will be added to bath 5|. When, however, the resin is added to bath 6|, there will be no resin added to bath 5| but the carcasses will be accreted without resin in bath 5| and then introduced as described above into bath 6| containing resin, which results in the suction in former carrying the resin containing liquid through the carcass and incorporating resin into the carcass in the form shown in Fig. 9. In Fig. 9. the manifold 55, air pressure pipe 56', suction pipe 51' and valve 58' are similar to the corresponding parts described in connection with Fig. 8.

In Fig. 10 is shown a heating oven 10 through which the carcasses It may be passed for drying, hot air being introduced from any suitable source of supply through the pipe 1| and periorated discharge head 12, a chimney 13 or outlet pipe being provided as desired.

Having described my invention, I claim:

1. The method of making a filter member having a controlled degree of porosity, which comprises forming a water and fiber bath, adding synthetic resin in its water soluble stage to the bath, adding to the bath fine particles of inert material selected from a class consisting of diatomaceous earth, vermiculite, kieselguhr, and fullers earth, and thoroughly mixing the same in the bath, said resin constituting 3% to 7% by weight of the bath, controlling the degree of porosity of the filter member by regulating the amount of inert material added to the bath, accreting a fibrous filter carcass onto a porous former of the desired shape in the bath, removing the former and carcass from the bath, removing the carcass from the former, and drying the carcass whereby to form a fibrous shell adapted for use as a filter member in which the particles of inert material have been caused by the resin to be dispersed and uniformly distributed in the interstices between the fibers throughout the shell.

2. The method of making a filter member having a controlled degree of porosity, which comprises forming a water and fiber bath, adding synthetic resin in its water soluble stage tothe bath, adding to the bath fine particles of inert material selected from a class consisting of diatomaceous earth, vermiculite, kieselguhr, and fullers earth, and thoroughly mixing the same in the bath. said resin constituting 3% to 7% by weight of the bath, controlling the degree of porosity of the filter member by regulating the amount of inert material added to the bath, accreting a fibrous filter carcass onto a porous former of the desired shape in the bath, removing the former and carcass from the bath, removing the carcass from the former, and drying the carcass whereby to form a fibrous shell adapted for use as a filter member in which the particles of inert material have been caused by the resin to be dispersed and uniformly distributed in the interstices between the fibers throughout the shell and assembling a plurality of said shells to form a filter.

3, The method of making a filter member having a controlled degree of rosity which consists in accreting onto a former in a first fibrous pulp bath a pair of outer shells, making a second water and fiber bath, adding synthetic resin in its water soluble stage to said second bath, adding to said bath fine particles of inert material selected from a class consisting of diatomaceous earth, vermiculite, kieselguhr, and fullers earth, thoroughly mixing the same in the bath. said from the first bath and second bath and drying them, and securing the inner pair of shells within the outer pair of shells with the shells spaced apart laterally from each other except at their edges, whereby the outer shells will be of coarser porosity to filter out the coarser particles of fluid being filtered and the inner shells will be of finer porosity to filter out the finer particles of the fiuid being filtered.

EDWARD O. SLOAN. 

